Apparatus for mechanically converting the oscillating movement of an electro-mechanical oscillator



NOV. 7, 1967 V E 1 3,351,788

I APPARATUS FOR MECHANICALLY CONVERTING THE OSCILLATING MOVEMENT OF AN ELECTRO-MECHANICAL OSCILLATOR Filed Feb. 1, 1966 I 2 Sheets-Sheet 1 Nov. 7, 1967 R FAVR 3,351,788

APPARATUS FOR MECHANIC/{LILY CONVERTING THE OSCILL NG OV EM RO-MECH M ENT OF AN ELECT ANICAL OSCILLATO Filed Feb. 1, 1966 2 Sheets-Sheet 2 APPARATUS FOR MECHANICALLY CONVERTING THE OSCILLATING MOVEMENT ORAN ELEC- TRO-MECHANICAL OSCILLATOR Robert Favre, Lausanne, Switzerland, assignor to Fabriques Movado, La Chaux-de-Fonds, and Manufacture des Montres Universal, Perret Freres S.A., Geneva, Switzerland Filed Feb. 1, 1966, Ser. No. 524,350 3 Claims. (Cl. 310-22) This application isin part a continuation of my previous application Ser. No. 196,817, filed May 22, 1962, now Patent No. 3,248,623.

This invention relates to apparatus for mechanically converting the oscillating movement of an electro-mechanical oscillator, preferably an oscillator for timepieces, into the rotary movement of a ratchet wheel.

Previously known apparatus of'this kind operated with only one driving pawl, and during the advance movement this pawl moved the ratchet wheel forward at least through a distance corresponding to the tooth interval of the ratchet wheel. Further means were then provided which prevented a return movement of the ratchet wheel during the returning movement of the driving pawl. In this known apparatus, therefore, in each case only one of the two half-oscillations of the mechanical oscillator was used for driving the ratchet wheel.

The invention aims to solve the problem of providing an improved apparatus in which on the one hand both half-oscillations of the mechanical oscillator can he used for directly driving the ratchet wheel and on the other hand additional means for braking the ratchet wheel during the returning movement of the pawl can be dispensed with.

In order to solve this problem, the present invention provides apparatus for mechanically converting the oscillating movement of an electro-rnechanical oscillator, preferably an oscillator for timepieces, into one-directional rotation of a toothed ratchet wheel, said oscillator comprising two mechanical oscillating arm-like pawls, the free ends of said pawls being adapted to engage the teeth of said ratchet wheel, the movement of said pawls having a component tangentially to the periphery of the ratchet wheel in such a manner that during one half-oscillation of said pawls one of said pawls engages and rotates the ratchet wheel while the other pawl is disengaged from the teeth of said ratchet'wheel and performs a movement which is directed tangentially to the periphery of the ratchet wheel but opposed to the tangential direction of movement of the periphery of said ratchet wheel until it reaches the next tooth interval and engages the teeth again, whilst during the other half-oscillation of said pawls the last-mentioned pawl upon engaging the teeth rotates the ratchet wheel while the first-mentioned pawl is disengaged from the teeth and performs its tangential movement opposed to tangential movement of the ratchet wheel.

An embodiment of the invention chosen by way of example is described hereunder with reference to the accompanying drawings illustrating a torsion oscillator of which the oscillations are maintained by electrical means.

In these drawings, 7

FIGURE 1 shows a torsion oscillator.

FIGURES 2 and 3 show sections III-III, respectively, of FIGURE 1.. v

FIGURE 4 diagrammatically illustrates a ratchet wheel and two driving pawls cooperating with this 'wheel.

In the embodiment shown in FIGURE 1, the timepiece has a base 1 which is secured to the plate of the timepiece and to which two torsion springs 2 of cruciform on lines IIII and cross-sectional shape are secured. A respective oscillating plan view of an electromechanical.

arm} is arranged at the top of each of these springs. The characteristics of these torsion springs and the way in which they mounted are already known.

The two arms 3 are side by side and parallel to one another and oscillate, in a plane parallel to the surface of the timepiece mechanism about the axes of their torsion springs. They extend over the major portion of the surface of the timepiece mechanism, from one end to the other, so that their moment of inertia with respect to their axes ofoscillation is as large as possible.

At each end of each of the two oscillating masses is arranged a bar magnet 4 and 14, respectively, of which i the two poles pass, during the oscillating movement, in

front of air gaps 5 and 6 each formed by two armature parts 7 and 8, and 10 and 7, respectively.

The armature parts consist of soft iron. The outer armature parts 7 are U-shaped, and the plane formed by the two arms of the U lies in the plane of oscillation of the system, whereas the two central armature parts 8, 9 and 10 are each in the form of an H of which the transverse bar 9 is wide and is disposed parallel to the plane of 0scillation of the system. The transverse bar 9 of the armature parts on one sideof the system at the same time forms the core of a control coil 11, whereas the corresponding transverse bar 9 of the armature parts on the other side of the system forms the core of a working coil disposed symmetrically with respect to the control coil.

The external magnetic field of each of the permanent magnets 4 and 14 is closed through two iron paths, that is to say, through the armature part 7.0n one side and through the armature parts 8, 9 and 10, 9, respectively, on the other side. In this way, during the oscillation of the permanent magnets a periodic change in magnetic flux is produced in each of the two armature parts co-operating with a permanent magnet, and this change is of opposite sign in these two armature parts, but the magnetic resistance of the whole circuit remains constant.

Disturbances of the period of oscillation determined by the mechanical elements are thereby avoided.

The change in the flux in the core 9 on the control side induces a current pulse in the control coil 11 which is the base-emitter circuit of a transistor, and this current pulse brings the transistor into the conducting state. The collector current which now flows through the transistor excites the working coil 12 which is in the output circuit 7 of this transistor; the working coil then acts on the magnets 14 at the working ends of the two oscillating arms 3, whereby the oscillating arms 3 receive mechanical impulses periodically transmitted by pawls 15'to ratchet wheel 16.

The two arms 3 oscillate the same frequency but in opposite directions at each instant, and therefore the changes of flux in the cores 9 of the control coil and working coil, co-operating with the two magnets 4 or 14 respectively, are always added to one another; this form of oscillation also ensures that the system is in a state of dynamic balance. The frequency of oscillation of the system can be adjusted by means of screws arranged at the ends of the oscillating arms.

FIGURE 4 shows a mechanism for converting the oscillating movement of the arms 3 into a rotary moveeach instant, and their ends are so formed that the two pawls can operate alternately, that is to say, movement of one pawl corresponds to a returning movement of the other pawl. The simultaneous use oftwo pawls of this kind makes it possible to drive the ratchet the driving a) wheel with forward movements of which the amplitude is only about one half as large as the tooth pitch of this ratchet wheel; this makes possible the use of ratchet wheels of which the tooth pitch is larger than would be possible if only one pawl used without separate blocking means.

It will thus be understood that the movement of the pawls have a component directed tangentially to the periphery of the ratchet wheel in such a manner that during one half-oscillation of said arms one of said pawls engages and rotates the ratchet wheel while the other pawl is disengaged from the teeth of said ratchet wheel and performs a movement which is directed tangentially to the periphery of the ratchet wheel but opposed to the tangential direction of movement of the periphery of said ratchet wheel until it reaches the next tooth interval and engages the teeth again, whilst during the other halfoscillation of said pawls the last-mentioned pawl is disengaged from the teeth and performs its tangential movement opposed to tangential movement of the ratchet wheel.

Thus the ratchet wheel is successively rotated by the one and the other pawl so that each takes along the ratchet wheel in one direction at an angle which corresponds to half the distance between two adjacent teeth.

In order that always one pawl can drive the ratchet wheel and the other pawl simultaneously disengage this wheel, the flanks of each tooth have a saw-tooth shape (as shown in FIGURE 4) so that the pawl, which does not drive, can slide off the long flank which is more tangentially inclined.

What is claimed is:

1. Apparatus for mechanically converting oscillating movement into one-directional movement in a timepiece having a plate, two torsion springs secured thereto and a toothed ratchet wheel driving the timepiece gearing comprising:

(A) two elongated oscillating masses, positioned parallel to one another and oscillating about the axes of 5 said torsion springs,

(B) electric means for keeping up the oscillations of said masses; (C) two resilient pawls each secured to one of said oscillating' masses, said pawls having ends adapted to mesh with the teeth of said ratchet Wheel, said ratchet wheel being successively rotated by one and then by the other of said pawls the driving movement of one pawl corresponding to the return movement of the other.

2. Apparatus according to claim 1, wherein said ratchet References Cited UNITED STATES PATENTS Hooker 74129 Atchley 310-36 Hetzel 3lO-21 X Tschudin 310-22 MILTON O. HIRSHFIELD, Primary Examiner,

D. DUGGAN, Assistant Examiner. 

1. APPARATUS FOR MECHANICALLY CONVERTING OSCILLATING MOVEMENT INTO ONE-DIRECTIONAL MOVEMENT IN A TIMEPIECE HAVING A PLATE, TWO TORSION SPRINGS SECURED THERETO AND A TOOTHED RATCHET WHEEL DRIVING THE TIMEPIECE GEARING COMPRISING: (A) TWO ELONGATED OSCILLATING MASSES, POSITIONED PARALLEL TO ONE ANOTHER AND OSCILLATING ABOUT THE AXES OF SAID TORSION SPRINGS, (B) ELECTRIC MEANS FOR KEEPING UP THE OSCILLATIONS OF SAID MASSES; (C) TWO RESILIENT PAWLS EACH SECURED TO ONE OF SAID OSCILLATING MASSES, SAID PAWLS HAVING ENDS ADAPTED TO MESH WITH THE TEETH OF SAID RATCHET WHEEL, SAID RATCHET WHEEL BEING SUCCESSIVELY ROTATED BY ONE AND THEN BY THE OTHER OF SAID PAWLS THE DRIVING MOVEMENT OF ONE PAWL CORRESPONDING TO THE RETURN MOVEMENT OF THE OTHER. 